Answer:
The error he did was that in place of 3(2x) he wrote 3x
i.e. the error was in the second term of the expression.
Step-by-step explanation:
We are given that:
f (x) = -x² + 3x + 1 and g(x) = 2x
f(g(x))=f(2x)
= -(2x)²+3(2x)+1
= -4x²+6x+1
But, student wrote it as:
f (g (x)) = -(2x)² + 3x + 1 = -4x² + 3x + 1
On comparing our work with the students work, we see that
The error he did was that in place of 3(2x) he wrote 3x
i.e. the error was in the second term of the expression.
